Every time I’ve used them I’ve printed off the address/shipment label.
The label has a barcode the courier needs to scan on collection.
If you choose DX (who won’t collect until Thursday)) instead of DHL they will bring a label with them, if you look on the Parcel Monkey site all the couriers are marked as to whether or not you need a printer to use the service.
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!